// Adds transformation (string1 => string2 : value) to the trie t
int addToTrie(Trie *t, wchar_t *string1, int strLen1, wchar_t *string2, double value){
TrieNode *tmp;
/* if the trie is empty ... */
if(t->firstNode == NULL){
t->firstNode = newTrieNode(*string1);
tmp = t->firstNode;
if((strLen1-1) == 0)
tmp->replacement = newEndNode(string2, value);
else
addToTrieDepth(tmp, string1+1, strLen1-1, string2, value);
return 0;
}
tmp = t->firstNode;
TrieNode *prev;
prev = NULL;
/* find common prefix from the trie */
while(strLen1 > 0){
/* if the left side already exists, add replacement to its ending node */
if(strLen1 == 1 && tmp->label == *string1){
addEndNode(tmp,string2, value);
return 0;
}
/* if the label matches, proceed to the next level in depth */
else if(tmp->label == *string1 && tmp->nextNode != NULL){
prev = tmp;
tmp = tmp->nextNode;
string1 = string1 + 1;
strLen1--;
}
/* if we are at the end of known prefix, expand */
else if(tmp->label == *string1 && tmp->nextNode == NULL){
addToTrieDepth(tmp, string1+1,strLen1-1, string2, value);
return 0;
}
/* if labels did not match, check the next node in the same depth level ...*/
else if(tmp->rightNode != NULL)
tmp = tmp->rightNode;
else break;
}
/* if common prefix was not found or was incomplete, a new branch must be started */
tmp->rightNode = newTrieNode(*string1);
tmp->rightNode->prevNode = prev;
tmp = tmp->rightNode;
if(strLen1 == 1)
addEndNode(tmp,string2, value);
else
addToTrieDepth(tmp, (string1+1),strLen1-1, string2, value);
return 0;
}
int main() {
struct TrieNode *root = newTrieNode();
insert(root, "hello");
printf("%d\n", search(root, "hel"));
free(root);
return 0;
}
//Driver function.
int main()
{
/* Change third ipAddress for validation */
char ipAdd[][MAX] = {"107.108.11.123", "107.109.123.255",
"74.125.200.106"};
char URL[][50] = {"www.samsung.com", "www.samsung.net",
"www.google.in"};
int n = sizeof(ipAdd)/sizeof(ipAdd[0]);
struct trieNode *root = newTrieNode();
// Inserts all the ip address and their corresponding
// domain name after ip address validation.
for (int i=0; i<n; i++)
insert(root,ipAdd[i],URL[i]);
// If reverse DNS look up succeeds print the domain
// name along with DNS resolved.
char ip[] = "107.108.11.123";
char *res_url = searchDNSCache(root, ip);
if (res_url != NULL)
printf("Reverse DNS look up resolved in cache:\n%s --> %s",
ip, res_url);
else
printf("Reverse DNS look up not resolved in cache ");
return 0;
}
// This method inserts an ip address and the corresponding
// domain name in the trie. The last node in Trie contains the URL.
void insert(struct trieNode *root, char *ipAdd, char *URL)
{
// Length of the ip address
int len = strlen(ipAdd);
struct trieNode *pCrawl = root;
// Traversing over the length of the ip address.
for (int level=0; level<len; level++)
{
// Get index of child node from current character
// in ipAdd[]. Index must be from 0 to 10 where
// 0 to 9 is used for digits and 10 for dot
int index = getIndex(ipAdd[level]);
// Create a new child if not exist already
if (!pCrawl->child[index])
pCrawl->child[index] = newTrieNode();
// Move to the child
pCrawl = pCrawl->child[index];
}
//Below needs to be carried out for the last node.
//Save the corresponding URL of the ip address in the
//last node of trie.
pCrawl->isLeaf = true;
pCrawl->URL = new char[strlen(URL) + 1];
strcpy(pCrawl->URL, URL);
}
// Adds string1 to trie, while expanding only downwards (in depth) via nextNode links
int addToTrieDepth(TrieNode *node, wchar_t *string1, int strLen1, wchar_t *string2, double value){
TrieNode *tmp;
/* more than 1 letters to add */
if(strLen1 > 1){
node->nextNode = newTrieNode(*string1);
node->nextNode->prevNode = node;
return addToTrieDepth(node->nextNode, string1+1, strLen1-1, string2, value);
}
/* only 1 letter to add */
else{
tmp = newTrieNode(*string1);
tmp->prevNode = node;
node->nextNode = tmp;
tmp->replacement = newEndNode(string2, value);
}
return 0;
}
/**
* Constructs and returns a trie given a list of words.
*/
static TrieNode* buildTrie(char* dict[], int dictLength)
{
TrieNode* root = newTrieNode();
int d;
for(d = 0; d < dictLength; d++)
{
addTrieWord(root, dict[d]);
}
return root;
}
void insert(struct TrieNode *root, char *word) {
int i, length, index;
length = strlen(word);
if (length <= 0) return;
struct TrieNode *current = root;
for (i = 0; i < length; i++) {
index = word[i] - 'a';
if (current->children[index] == NULL) {
current->children[index] = newTrieNode();
}
current = current->children[index];
}
current->isWord = true;
}
/**
* Used by addTrieWord() to actually add a word to the trie, allocating any new
* nodes required.
*/
static void addTrieWordRecurse(TrieNode* node, char* word)
{
int index = *word - FIRST_ASCII_CH;
if(node->children[index] == NULL) {
node->children[index] = newTrieNode();
}
if(word[1] == '\0') {
node->children[index]->isWord = TRUE;
}
else {
addTrieWordRecurse(node->children[index], word + 1);
}
}
//--------------------------------------------------------------------------------------------------
// A utility function to insert a word to Trie
void insert(struct TrieNode** root, char* word, int index)
{
if (*root == NULL) // Base case
*root = newTrieNode();
if (*word != '\0') //Down - here we are calling insert as well as we are inserting
insert( &( (*root)->child[tolower(*word) - 'a'] ), word+1, index ); //ch into child array.
else // while recursion stack unwinding, it will go inside to else only once for last char '\0'
{
if ((*root)->isEnd) // Insert index of this word to end of index linked list
{ // going inside this means this word is already present in Trie DS
IndexNode* pCrawl = (*root)->head;
while( pCrawl->next )
pCrawl = pCrawl->next; // going till the last of the link.
pCrawl->next = newIndexNode(index);
}
else // If Index list is empty
{ // We are first time adding this word into Trie DS.
(*root)->isEnd = 1;
(*root)->head = newIndexNode(index);
}
}
}
